tess_linn,

I  now see that this post relates to your other "Challenge" post.  The image you posted above of your layers in photoshop was not large enough to see detail and it looked to me like your layer titled 'Original' was a texture template that would have been created from UV mapping your 3d model.  Having a layer titled BumpMap also indicated this.  Thats why I gave a workflow suggestion as I thought it may be helpful.   I can now see that it is actually parts of your 3d house that you have selected out of your rendering.   My suggestion to create a flats layer was to assist in painting a texture template to apply to the 3d house within your 3d program before rendering.  If you are working on the final rendered image of your house then photoshop has good selection tools to extract exactly what parts you want to separate onto different layers.

If you did want to try the method you mention in point 1. of your post above I would suggest that you render out of your 3d program two images.  One with the textures such as roof tiles, brickwork etc applied and the second one with the flat colours for easy selection in photoshop.  Just make sure that for the flat colour rendering you turn shadows off otherwise this would create shading in your house parts making selections with the magic wand harder.   So long as you don't move your camera between renderings you can then combine both renderings into the one .psd file.  To combine the renderings open both in photoshop.  Press ctrl+a to select the whole of one image then V to select the move tool.  Then hold down the ctrl key as you drag the selected image onto the other one.  This will place the dragged image exactly in the center of the second one so that selections you make on the flat colour layer match the textured layer.

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